Starting up a fired heater is one of the higher risk operator tasks that must be performed within a refinery or chemical plant. But if you can simplify the start-up process, you can free up operators to focus on other critical start-up tasks. One way of simplifying the fired heater light-off is the use of a minimum fire regulator.
Besides turndown, which is described in a previous post titled A Solution for High Turndown Applications; I have identified three ways that the minimum fire pressure regulator could help with fired heater start-ups:
1) Limit fuel gas used during start-up
With the minimum fire regulator you avoid the potential for supplying too much gas during start-up or, depending upon your valve configuration, “packing” the line with high pressure fuel gas between the control valve and burner block valve.
2) Reduce system complexity
If a minimum fire regulator is not used then in most cases steps must be taken in the burner management system (BMS) to limit how much the control valve can be opened during the start-up process. This is typically in the form of limit switches on the control valve that must be properly placed and routinely tested. Because the minimum fire regulator is controlling downstream pressure and sized only for start-up there is no additional equipment required to limit the regulator output.
3) Simplify start-up procedures
By using a minimum fire regulator you can reduce the number of procedural steps required to start-up the heater. Steps like finding the optimal position for the control valve for startup or staying within the fuel gas pressure limits can be avoided. By removing these steps you free up operators or in some cases even limit their involvement in this risky task.